Using compact fluorescent light bulbs is a great idea and can save more than $30 on each bulb you replace, even factoring in a higher purchase price.
But buying CFLs, as they're called, takes more knowledge than buying incandescent bulbs. That may be why they still make up only about 5 percent of the light-bulb market, according to Department of Energy estimates.
Incandescent bulbs are really little heaters that happen to give off a small percentage of their energy as light. Compact fluorescents are about four times more efficient and don't give off much heat at all. They also last eight to 15 times longer.
"If used in the right location, you'll be thrilled for years, and they'll save you a ton of money," said Wendy Reed, spokeswoman for the government's Energy Star program. "I know in our house, we have cut back our electricity bills a ridiculous amount."
Some tips on buying CFLs:
Take baby steps.
At a savings of more than $30 per bulb, consumers might be tempted to run out and buy CFLs for all their fixtures. But start with replacing your five most-used bulbs.
Think brightness, not watts.
The most basic relearning with CFLs is in looking at the wattage. We've been trained to know a 100-watt bulb is very bright and a 40-watt bulb is dimmer. But watts refer to how much energy the bulb sucks from your electrical system. CFLs use about a quarter of the energy. So, the equivalent of a 60-watt incandescent is a 15-watt CFL.
Brightness is more appropriately measured in lumens. For example, a traditional 60-watt bulb and a 15-watt CFL both produce about 800 lumens. More lumens means more light. The good news is you probably won't have to bother with these conversions. The packaging of many CFLs prominently displays its incandescent equivalent.
Follow the Star.
Buy CFLs certified as Energy Star, the government-backed labeling program for energy-efficient products.
Energy Star compact fluorescents will give the highest-quality light and save you the most money. Energy Star bulbs use at least two-thirds less energy than incandescents to provide the same amount of light and are likely to last 10 times longer. Certified bulbs generally turn on within one second, achieve full brightness within three minutes and produce no sound. They also must come with at least a two-year warranty.
The best deals on CFLs are in multipacks found at such retailers as Costco, Home Depot, Lowe's, Sam's Club, Wal-Mart and BJ's Wholesale. For a regular lamp bulb, a four-pack for $10, or $2.50 per bulb, is a good price.
Regular CFLs won't work with a dimmer switch. You'll have to find CFLs specifically labeled as dimmable.
When color counts.
If you want a similar light color as many incandescent bulbs, look for CFLs labeled 2,700 degrees Kelvin or "warm white." The color at 3,000 Kelvin will be neutral white, while those over 4,000 will be bluish-white, or "daylight."
CFLs contain a tiny amount of mercury. For that reason it's best not to dispose of them in the household trash. Get disposal options at www.earth911.org or call 1-877-EARTH911.
Gregory Karp writes for The Morning Call in Allentown, Pa.